Simple RSS limit test

test_mem_usage.rb

class TestMemoryUsage
  LIMIT_MB = 70 # the memory limit you want to test
  
  def run
    work_thread = Thread.new do
      # your ruby code here
    end

    loop do
      sleep(0.1)
      usage = check_memory_usage
      puts "#{usage}Mb"
      
      if usage > LIMIT_MB
        puts 'Memory usage got higher the limit'
        Thread.exit
      end

      break if !work_thread.status
    end
    
    work_thread.join
  end
  
  def check_memory_usage
    (`ps -o rss= -p #{Process.pid}`.to_i / 1024.0).round(2)
  end
end

TestMemoryUsage.new.run